Ubuntu: change editor globally

I found the update-alternatives on my travels and very handy it is too especially when on a bytemark box by default the editor is set to "joe". From the man page:

update-alternatives creates, removes, maintains and displays information about the symbolic links comprising the Debian alternatives system.
It is possible for several programs fulfilling the same or similar functions to be installed on a single system at the same time. For example, many systems have several text editors installed at once. This gives choice to the users of a system, allowing each to use a different editor, if desired, but makes it difficult for a program to make a good choice of editor to invoke if the user has not specified a particular preference.
Debian's alternatives system aims to solve this problem. A generic name in the filesystem is shared by all files providing interchangeable functionality. The alternatives system and the system administrator together determine which actual file is referenced by this generic name. For example, if the text editors ed(1) and nvi(1) are both installed on the system, the alternatives system will cause the generic name /sw/bin/editor to refer to /sw/bin/nvi by default. The system administrator can override this and cause it to refer to /sw/bin/ed instead, and the alternatives system will not alter this setting until explicitly requested to do so.